The present invention relates to devices for managing body fluids such as urine, sweat, saliva, blood, menses, purulence, or fecal material, and in particular to their ability to acquire and retain aqueous based materials. The invention further relates to disposable absorbent articles such as baby diapers or training pants, adult incontinence products, and feminine hygiene products and other body liquid handling articles such as catheters, urinals, and the like.
Devices for managing body fluids are well known in the art and are frequently used for a wide variety of purposes. For example, the devices may serve hygienic purposes such as diapers, sanitary napkins, adult incontinence products, underarm sweat pads, and the like. There is another class of such devices which serve medical purposes such as wound dressings or drainages, catheters, and the like. Accordingly such devices have been designed to cope with a large variety of different body liquids such as for example urine, sweat, saliva, blood, menses, purulence, fecal material, and the like.
It has been recognized in the prior art that it is desirable to have large open pores in the acquisition region of the device to be able to readily accept body liquids into those voids even at high delivery rates. In addition, it has been recognized that, depending on the use, a large void volume for acquisition and intermediate storage of the liquid gushes is required close to the loading point. Large void volume, however, creates unwanted bulk for the device. The bulk thus created is particularly undesirable close to the body exits from which the body liquids are discharged such as the urethra. In order to limit the unwanted bulk at least before the first acquisition of body liquid, it has been suggested in the prior art to compress the acquisition material. Examples for this are acquisition patches comprising chemically stiffened cellulose which have been compressed in the moist condition in order to create hydrogen bonding to hold the material thin before discharge is acquired such as those disclosed for example in European patent publication No. 0 512 010 (Cook et al.). Upon the first wetting of such a material, however, these material tend to irreversibly expand. Hence, all such materials still create unwanted bulk for the remainder of the usage period. Other acquisition material its which are thin until wetted for the first time have been disclosed in PCT patent publication No. WO94/13704 which teaches a polymeric foam material commonly known as high internal phase emulsions. Some of the latter materials will re-contract upon dewatering, but those materials acquire liquid too slow to be useful for acquiring large gushes sufficiently fast.
It is an object of the present invention to provide a liquid handling member which overcomes the problems posed by the prior art.
It is a further object of the present invention to provide a liquid handling member which expands upon liquid absorption and contracts upon liquid desorption while having a short absorption time for the absorption of 80% of its total liquid capacity.
It is a further object of the present invention to provide a device for managing body liquids which comprises a liquid handling member of the present invention.
It is a further object of the present invention to provide disposable absorbent articles such as a baby diaper which comprises a liquid handling member according to the present invention.
The present invention provides a liquid handling member which is characterized in that said liquid handling member has a contraction factor of less than 0.8 after the first test cycle and an expansion factor of at least 1.25 after the first test cycle according to the reversible volume expansion test defined herein. The liquid handling member of the present invention further has a 80% absorption time of less than 2 seconds according to the Demand Absorbency Test defined herein.
It is another aspect of the present invention to provide a device for handling body liquids which comprises a liquid handling member according to the present invention.